I don't like Bitdefender 2008. I installed it once on my laptop and it totally bogged it down. So, I try uninstalling it........ it wasn't having that either. I haven't heard of ESET smart security though, I am just throwing in my 2 cents about Bitdefender.
Ah yes, I actually have heard good things about NOD32. Unfortuanetly, I don't have any personal experience with that software. Maybe some other people on here might have some other opinions about it.